Main entry point for adding an editor. Adds the editor to the layout in the given
stack, and notifies the workbench page when done.
Parameters: ref - editor to add Parameters: workbookId - workbook that will contain the editor (or null if the editorshould be added to the default workbook)
Returns the active editor in this perspective. If the editors appear
in a workbook this will be the visible editor. If the editors are
scattered around the workbench this will be the most recent editor
to hold focus.
the active editor, or null if no editor is active
Brings an editor to the front and optionally gives it focus.
Parameters: part - the editor to make visible Parameters: setFocus - whether to give the editor focus true if the visible editor was changed, false if not.